Filament winding and impregnation mechanism



Jan. 27, 1970 -H. J. HIRTZER FILA-MENT WINDING AND IMPREGNATION MECHANISM 2 Sheets-Sheet l z 1 4., 4 m o D Filed Sept. I 23, 1965 INVENTOR. HENRY J H/RTZER BY mM V ATTORNEYS Jan. 27, 1970 H. J. HIRTZER FILAMENT WINDING AND IMPREGNATION MECHANISM 2 Shee ts-Sheet 2 Filed Sept. 23, 1965 5 5 INVENTOR.

HENRY J. H/RTZER B I Z0, M

TORNEYS United States Patent ABSTRACT OF THE DISCLOSURE An apparatus and method for impregnating a filament with resin while passing the filament through a resin bath in which the filament is passed through an orifice while immersed in the resin, resulting in an increased resin pressure at the orifice to force the resin into the filament.

This invention relates generally to apparatus for impregnating filaments with resins or the like and thereafter winding the impregnated filaments to form a tube or other object, and is more particularly directed to an improved mechanism of this variety having a relatively high speed of processing the filaments.

Plastic pipes or tubes are frequently formed by impregnating filaments of glass or the like with a suitable resin such as polyester, epoxy, et cetera, and thereafter winding the impregnated filaments about a cylindrical forming mandrel. The wound resin impregnated fibers become bonded to each other to thereby form an integral pipe or tube. In a similar manner other objects may be formed by employment of mandrels of other configurations in conjunction with appropriate variation of the path over which the impregnated filaments are wound. Heretofore the speed with which the filaments are fed during impregnation and winding has been limited by the relatively long residence time of the filaments in an impregnation bath required to insure complete impregnation prior to winding. More particularly, it has been the usual practice to pass the filaments alternately above and below a series of rollers disposed in an impregnation bath on a feeder for winding the filaments about the forming mandrel. In accordance with this procedure, a relatively long tortuous path through the bath is required, as well as a relatively long residence time therein to insure adequate impregnation of the filaments. The bath unit is accordingly of relatively large size. Moreover, the speed of filament travel is limited to about 2,000 inches per minute.

It is therefore an object of the present invention to provide improved filament impregnating and winding apparatus for processing filaments at materially increased feed speeds up to about 10,000 inches per minute.

Another object of the invention is the provision of apparatus of the class described having a relatively compact impregnation bath unit.

Still another object of the invention is to provide filament impregnating and winding apparatus having a simplified mechanism for maintaining a desired constant tension on the filaments during processing.

It is further object of the invention to provide apparatus of the class described having a two-fold impregnation arrangement for insuring complete impregnation of filaments under even the worst adverse conditions.

A still further object of the invention is the provision of filament impregnating and winding apparatus of relatively simple, low cost design.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form 3,492,187 Patented Jan. 27, 1970 of the invention which is illustrated in the drawings accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claims.

FIGURE 1 is a plan view of filament impregnating and winding apparatus in accordance with the invention.

FIGURE 2 is an elevational view taken at line 2-2 of FIGURE 1.

FIGURE 3 is an enlarged elevational View of the impregnating unit of the apparatus.

FIGURE 4 is a fragmentary elevational view taken at line 4-4 of FIGURE 3.

FIGURE 5 is a fragmentary elevational view taken at line 5-5 of FIGURE 3.

FIGURE 6 is a detail view illustrating the two-fold impregnation arrangement of the apparatus.

FIGURE 7 is a fragmentary perspective view of the filament feeder of the apparatus.

Referring now to the drawings, FIGURES 1 and 2 in particular, filament impregnating and Winding apparatus in accordance with the invention will be seen to basically include a plurality of bobbins 11 rotatably disposed upon upright posts 12 and carrying filaments 13 of glass fiber,

or the like. The filaments are guided through an impregnation bath unit 14 to a feeder 16. In the illustrated case, the feeder is arranged to travel back and forth parallel to a rotating cylindrical mandrel 17. In this regard, a drive motor 18 may be provided to rotate the mandrel by means of a belt or chain drive, and a drive motor 19 may be coupled to the feeder by means of a belt or chain drive to translate same back and forth parallel to the mandrel in a manner subsequently described. During translation of the feeder it plays out the filaments 13 to the rotating mandrel which winds the filaments thereabout. Prior to such winding of the filaments, they are impregnated with resin in the bath unit 14. Thus during winding, the impregnated filaments band together to form a cylindrical pipe or tube about the mandrel which may 'be subsequently withdrawn in accordance with conventional practice.

It will be appreciated that to the extent described to this point, the impregnating and winding apparatus is substantially conventional. However, in conventional apparatus the residence time of the filaments in the impregnation bath unit is relatively long to insure com plete impregnation. As a result, the speed with which the filaments may be processed and fed upon the mandrel is limited. In addition, the conventional bath units are relatively large.

The present invention overcomes the aforementioned difiiculties by means of the impregnating bath unit 14 which is relatively compact and yet arranged to provide complete impregnation in an extremely short residence time. To these ends, the bath unit includes an open-topped supply tank 21 for containing impregnating resin. A tapered open topped control tank 22 of substantially rectangular cross-section depends into the supply tank from overlying horizontal cross members 23 of a superstructure 24. Opposite sides of the control tank 22 are provided adjacent their lower ends with ports 26 of preferably semi-circular configuration, as best shown in FIG- URE 3, to facilitate the admission of resin to the control tank from the supply tank. A bar 27 having a plurality of coaxially spaced outwardly flared annular flanges 28 extends across the lower end of the control tank in close spaced relation to the bottom thereof to define a plurality of orifices 30 for the passage of the filaments beneath the bar. The bar is preferably supported in such position by means of a plate 29 vertically disposed within the control tank centrally between the sides thereof. The

plate partitions the control tank into two substantially separate parts in communication with each other substantially only through the limited space beneath the bar. For reasons subsequently described, the plate is preferably of springy material and is edge secured to the superstructure cross members 23 with a portion projecting upwardly therefrom. The filaments 13 extend from the bobbins 11 between the fingers of a guide comb 31 mounted upon the superstructure, over a bar or roller 32, which can be journaled for rotation between the superstructure cross members 23, and under the bar 27 between the flanges 28 thereof through the orifices 30. The filaments then extend upwardly from the bar 27 and over another bar or roller 33 which can be journaled for rotation between the superstructure cross members, between the fingers of a guide comb 34, and to the feeder 16 for winding about the rotating mandrel 17.

With the impregnating bath arrangement just described, the filaments 13 in being pulled under the bar 27 through the orifices 30 create a pressure in the orifices by virtue of the limited clearance between the bar and the bottom of the control tank 22. This pressure acts to remove any air entrained in the filaments and force the resin into the filaments to very effectively impregnate same. More particularly, the filaments, as they pass under the bar through the orifices, pull the resin with them and by virtue of the limited clearance an impregnating pressure is established. In this regard with the configuration of the orifices shown in the drawing, a clearance of between about ,3 and /8 inch between the bar and bottom of the tank has been found to be particularly effective,

in establishing the desired impregnating pressure. Like- Wise a spacing between the flanges 28 of approximately twice the diameter of the filaments has been found to enhance the impregnating action. It is to be realized, of course, that the orifices 30 can have other configurations than that shown. For example, the orifices could have a configuration to form the filament into a particular cross-sectional shape such as a flattened shape.

Although impregnation of the filaments in the foregoing manner is suitable for most applications, the impregnating bath unit 14 preferably includes a further impregnating mechanism such that a two-fold impregnating action is provided to insure complete impregnation under all conditions that may be encountered. More particularly means such as a bar or roller is provided to squeeze the filaments as they pass over roller 33. In the embodiment depicted, a squeeze roller 36, preferably of hard rubber or similar material is journaled for rotation parallel to and closely adjacent the roller 33 for this purpose. The squeeze roller is disposed rearwardly of the roller 33 relative to the direction of filament movement with the lowermost level of the squeeze roller being lower than the uppermost level of the roller 33. The filaments in passing upwardly out of the control tank are thus squeezed between the rollers 33, 36 in transit to the feeder 16. Such filaments are flattened by the rollers to permit escape of entrained air and balls 37 of resin are produced at the nip of the rollers, which balls of resin wash back over the filaments and are forced therein to provide further impregnation. It has been found in general that the rollers should be disposed such that a plane through their axes is at an angle of no more than 45 from the vertical in order that gravitational forces acting on the resin will not be great enough to prevent the balls from forming. The optimum angle is dependent upon the viscosity of the particular impregnating resin that is utilized. In this regard, for polyester and epoxy resins, which have viscosities of approximately 1,500 centipoises, an angle of 22 provides optimum results. As in the case of the impregnating action produced by the pressure beneath the bar 27, the impregnating action provided by the balls of resin maintained at the nip of the rollers 33, 36 is in itself sufficient to effect complete impregnation of the filaments in most instances. However, the combination of the two mechanisms is preferred to insure impregnation under all operating conditions.

The impregnation tank unit 14 also maintains a desired amount of tension on the filaments during the overall impregnating and winding process without requirement of the expensive automatic tension control devices typically associated with bobbins in a filament winding machine. More particularly, the pressure created in the orifices 30, besides impregnating the filaments 13, also places tension on them between the orifices and the mandrel. If this tension should become too great, or there is a momentary snag at one of the bobbins, the spring plate 29 flexes to the left or right, respectively, as viewed in FIGURE 3. This enlarges the area between the bar 27 and the bottom of tank 22. Consequently, the pressure causing the tension on the filaments is 'reduced and they are prevented from breaking. Further tension is provided on the filaments by the pressure between squeeze rollers 36 and roller 33. If the bar 27 imparts too much tension to the filaments, the total tension, on the filaments is also relieved to a certain extent by a coaction between the squeeze roller 36 and the bar 27. That is, squeeze roller 36 is preferably secured to the upper portion of the spring plate 29 above the superstructure cross members. Thus, the edge support of the plate between the cross members is intermediate the bar 27 and squeeze roller 36. Accordingly, if the bar 27 imparts too much tension to the filaments passing thereunder, the lower portion of the spring plate tends to be flexed to the left; as viewed in FIGURE 3. The upper portion of the plate, being on the opposite side of the edge support thereof, is correspondingly flexed somewhat to the right. As a result, the squeeze roller is displaced away to an extent from the roller 33 to release the tension placed on the filaments by these rollers and thus the tension at the bar 27.

Besides the placing of tension on the filaments by the impregnation tank obviating the necessity of tension control devices on the bobbins, it eliminates the need for elaborate guides and pulleys for the filaments between the bobbins and the tank.

Means are provided to facilitate adjustment of the amount of pressure between the rollers 33, 36 so that the tension on the filaments and the degree of flattening and impregnation thereof can be selectively varied. In this regard, the upper portion of the spring plate 29 is advantageously formed with an upwardly and rearwardly inclined section 38. The inclined section engages the tip of a jack screw 39 mounted upon the superstructure. The jack screw may be selectively raised or lowered to in turn respectively increase or decrease the pressure between the squeeze roller 36 and roller 33.

The filaments 13, completely impregnated and suitably tensioned by the bath unit 14 in the manner hereinbefore described are thereafter pulled to the feeder 16 for distribution to the mandrel 17 and winding thereon. The feeder, as best shown in FIGURE 7, includes a horizontal platform 41 which extends parallel to the mandrel and is provided with sprockets 42 at its opposite ends journaled for rotation about vertical axes. One sprocket is coupled to the motor 19 and a chain 43 extending in a continuous loop about the sprockets is thereby driven upon the platform. A rod 44 mounted on the platform in elevated position serves as a guide for a carriage 46 having a sleeve 47 slidably engaging same. A fixed feeder comb 48 is mounted at the rear of the carriage while a swivelablefeeder comb 49 is mounted at the front of the car- 'riage in transverse alignment with the fixed comb. Driving of the carriage is facilitated by means of a slot 51 extending transversely of the carriage and receiving a pin 52 projecting upwardly from a link of the chain. The filaments extend through the feeder combs and about the mandrel. The pin 52 engaging the slot 51, effects driving of the carriage alternately back and forth parallel to the mandrel as the chain moves along its closed loop path. In this regard, when the carriage reaches either of the sprockets, the pin moves to the opposite end of the slot as the chain passes around the sprocket. The carriage is thereafter pulled in the reverse direction to the opposite end of the platform 41 where the direction of carriage movement is again reversed in an analogous manner. The feeder carriage thus moves alternately back and forth to deliver the filaments to the rotating mandrel, the swivelably mounted comb pivoting to follow the carriage movement and appropriately direct the filaments upon the mandrel. The resin impregnated filaments wound upon the mandrel band together to form a cylindrical pipe or tube.

It is, of course, to be realized that all metal surfaces which the filaments come into contact after tension is placed thereon by the impregnation tank should be polished so that they will not fray or break the filament strands.

Many variations and modifications can be made in the invention Without departing from the scope thereof. For example, two or more bath units and feeders can be used simultaneously in winding pipe on one mandrel. That is, a bath unit and feeder can be provided on each side of the mandrel, or several can be stacked vertically on one side of the mandrel. This would permit a substantial reduction in the amount of time it takes to form a cylinder or pipe and allow alternate layers of the filaments to have various difference helical pitches to alter the stiffness characteristics of the finished product. In addition, several bath units and feeders can be placed side by side along the length of a long mandrel so that an especially long cylinder can be formed, or more than one cylinder can be simultaneously formed on one mandrel.

In some instances it is advantageous to pre-wet the filaments such as with a sizing before they are coated with a resin. To accomplish this, the filaments can be passed through two bath units before they reach the feeder-one to pre-wet the filaments and the other to impregnate them with resin.

What is claimed is:

1. In a filament impregnating and winding apparatus, an impregnating bath unit comprising a tank for containing resin, a plate member dividing said tank into two parts, said plate member defining a plurality of orifices with each such orifice being adapted to receive one of the respective filaments, each orifice having a size and shape relative to the size and shape of the filament whereby movement of the filament therethrough will create an increased resin pressure within the orifice for forcing resin into the filament, and means for guiding moving filaments into said tank and through said orifices.

2. The combination of claim 1, further defined by said orifices being defined by a bar on said plate member being in closed spaced relation to the bottom of said tank and said means for guiding said filaments guides them around the lower portion of said bar member to establish said pressure for forcing said resin into said filaments in the limited space between said bar member and the bottom of said tank.

3. The combination of claim 2, further defined by the spacing between said bar member and the bottom of said tank being about A; to M inch.

4. The combination of claim 3, further defined by said bar member having a plurality of outwardly flared annular flanges coaxially spaced apart by a distance of about twice the diameter of said filaments.

5. The combination of claim 1 in which said orifices are defined by means on said plate member and the bottom of said tank.

6. In filament impregnating and winding apparatus, an impregnating tank unit comprising a tank containing impregnating resin, a :bar member disposed in said tank in close spaced relation to the bottom thereof, upper and lower engaged horizontal rollers disposed parallel to said bar in elevated relation to the level of resin in said tank, said upper roller having a lowermost portion at a level beneath that of an uppermost portion of said lower roller, a spring plate disposed in said tank and having said bar and upper roller secured at spaced positions thereof, said plate partitioning said tank into separate portions in communication through the space between said bar and bottom of said tank, means edge supporting said plate at a position intermediate said bar and upper roller, and means feeding filaments into said tank around the lower portion of said bar and between said upper and lower rollers.

7. The combination of claim 6, further defined by pres sure adjusting means operatively associated with said plate for selectively urging the portion thereof to which said upper roller is secured towards or away from said lower roller to regulate the pressure between said upper and lower rollers.

8. The combination of claim 7, wherein said plate has an inclined portion upwardly from said upper roller, and said pressure adjusting means comprises a jack screw having its end engaging said inclined portion of said plate.

9. Filament impregnating and winding apparatus comprising a rotary mandrel, a filament feeder disposed adjacent said mandrel and adapted for translation parallel to the axis thereof to feed filaments to said mandrel for winding thereon, an open-topped impregnating supply tank containing resin, a tapered control tank disposed Within said supply tank and having ports adjacent its lower end to admit resin thereto from said supply tank, a horizontal bar member disposed in said control tank in close spaced relation to the bottom thereof, upper and lower engaged horizontal rollers disposed parallel to said bar in elevated relation to the level of said resin in said control tank, said upper roller having a lowermost portion at a level beneath that of an uppermost portion of said lower roller, a spring plate disposed in said control tank and having said bar member and upper roller secured at vertically spaced positions thereof, said plate partitioning said tank into separate portions in communication through the space between said bar member and. bottom of said control tank, means edge supporting said plate at a position intermediate said bar member and upper roller, bobbin means carrying a pluraltiy of filaments, and means guiding said filaments from said bobbin means under said bar member through said rollers to said feeder for distribution to said mandrel.

10. Apparatus according to claim 9, further defined by said feeder comprising a horizontal platform, a continuous chain mounted on said platform, said chain having a pin projecting vertically therefrom, and a feeder carriage having comb means for distributing said filaments, said carriage having a slot transverse to said platform and receiving said pin.

References Cited UNITED STATES PATENTS 2,741,294 4/ 1956 Pancherz 156-180 2,748,831 6/1956 Nash 156425 2,948,649 8/1960 Pancherz 156180 3,307,998 3/1967 Boggs 156-361 3,366,522 1/1968 Underwood 15669 FOREIGN PATENTS 238,021 9/1959 Australia.

HAROLD ANSHER, Primary Examiner D. J. FRIT SCH, Assistant Examiner US. Cl. X.R. 

